Abstract
Interspersal procedures have been used to decrease challenging behavior and facilitate skill acquisition. However, little is known about the effect of interspersing mastered tasks that are similar versus dissimilar to the target task. This study examined the effects of different teaching conditions on the acquisition, maintenance and generalization of novel sight words by four children with autism. Rates of challenging behavior and participant preference data are also reported. Phase 1 compared teaching conditions with and without interspersed trials, and the results showed that all four participants acquired more sight words when mastered tasks were interspersed during teaching. Phase 2 compared the interspersal of mastered sight words (similar) and mastered motor imitation (dissimilar). For two participants interspersal of similar tasks resulted in the acquisition of more words, for one participant results were mixed, and one participant acquired slightly more words when dissimilar tasks were interspersed. Rates of challenging behavior throughout the study were low but variable across all conditions. Higher rates of challenging behavior for some participants were observed during baseline. Participants preferred interspersal to no interspersal and interspersal of similar tasks to dissimilar tasks. Implications for the motivation and learning of children with autism are discussed.